Using time-resolved small-angle x-ray scattering (SAXS), we will measure the rate of compaction undergone by an unfolded protein when it is suddenly placed under native conditions. SAXS is the only time-resolved experimental probe which can give an overall size and shape indication of the conformational state of a protein. SAXS data may be used to determine the radius of gyration; to obtain shape information which may be inferred from the Kratky plot and the pair distribution function; and to determine the association state of a protein sample. Time-resolved SAXS measurements of cytochrome c refolding show the formation of an association state within the dead time of the stopped-flow mixer. We have shown that the degree of association can be reduced by using lower protein concentration and a higher final denaturant concentration.